java string replace using pattern code example

Example 1: string replace java

public static void main(String args[]){  
String s1="my name is khan my name is java";  
String replaceString=s1.replace("is","was");//replaces all occurrences of "is" to "was"  
System.out.println(replaceString);  
}}

Example 2: java string regexp replace

String input = "abcd";
Pattern p = Pattern.compile("regexp");
String output = p.matcher(input).replaceAll("replacement");